Conventional indexable cutting tools use different systems for fixing or clamping a cutting insert depending on uses. For example, for light cutting processing, as used in machining for outside diameter or finishing, in which a cutting insert does not receive a high cutting resistance, a clamping system using an L-shaped lever placed inside a body is used since priority is given to easy replacement of cutting inserts (see, for example, PTL 1). This type of lever generally has a rod-shaped lever body, a clamp portion protruding laterally from one end of the lever body for pressing a cutting insert, and a protrusion provided in the middle of the lever body and protruding outwardly in a radial direction. According to this clamping system, the lever body is accommodated in a hole penetrating a body such that the clamp portion of the lever is positioned in a through hole formed on the cutting insert. In this state, a force is applied to the other end of the lever body so that the lever is inclined, with the protrusion serving as a fulcrum, and the cutting insert is pressed against a side wall of an insert fixing portion (tip seat) of the body, with the clamp portion of the lever serving as a point of action, thereby fixing the cutting insert. On the other hand, for heavy cutting processing or the like with a high cutting resistance, a clamping system using a screw is used to obtain a greater clamping force.